I managed to log BLE communications with a Nordic chip based device I am interested in on my Android phone and loaded the log in Wireshark, applying
btatt as filter.
It uses some default BLE "transmissions" like "Battery Service: Battery Level" as well as UART for actual control. Wiresharks Info column shows e.g.:
Sent Write Request, Handle: 0x0011 (Nordic UART Service: Nordic UART Tx)
Rcvd Handle Value Notification, Handle: 0x000e (Nordic UART Service: Nordic UART Rx)
How can I set a filter to get only the UART Rx and Tx raw data as a list?